The present invention relates generally to methods and systems for measuring angles. Merely by way of example, embodiments of the present invention provide a system for acquiring and processing 360° images to provide high resolution angular measurements for surveying applications. However, the scope of embodiments of the present invention is broader than this particular application and can be applied to other applications utilizing angular measurements.
In some surveying operations, a horizontal angle, a vertical angle, and a distance to a target point are measured from a reference point. The measured data may be used to calculate the location of the target point using triangulation techniques. In many small-scale survey operations, one person is responsible for surveying the work site using one or more surveying tools.
A theodolite is a surveying instrument that is commonly used in determining the position of an object, particularly on inaccessible ground, with respect to a known position. The theodolite typically includes a telescope that is mounted so that it rotates about both vertical and horizontal axes. The theodolite also includes horizontal and vertical circular scales that are used in measuring the angular position of the telescope after it has been aligned to view a target. The horizontal angle (i.e., bearing) and the vertical angle (i.e., elevation) are read from the circular scales and compared with reference positions to determine the bearing and the elevation of the target with respect to the theodolite. These conventional theodolites require action on the part of the surveyor during operation, both for aligning the telescope on the target and for reading the bearing and elevation data from the circular scales.
In some electronic theodolites, angle encoder are utilized to replace the horizontal and vertical scales and automate the determination of the bearing and elevation. Typically, the instrument is zeroed and then as the instrument is rotated to view the target, the angle encoder provides an output including the angle of rotation. These electronic angle encoders are expensive and may not provide sufficient accuracy for particular applications. Thus, there is a need in the art for improved methods and systems for determining angles of targets with respect to a surveying instrument.